TW201520269A - Belt made of polyurethane and belt forming material - Google Patents

Abstract

This invention provides a transmission belt made of polyurethane, which exhibits excellent durability. More particularly, this invention provides a transmission belt, made of polyurethane which contains diisononyl 1,2-cyclhexane dicarboxylate ester represented by the following formulae (I).

Description

Polyurethane transmission belt and belt forming material

The present invention relates to a polyurethane transmission belt and a material for forming a belt.

Polyurethane transmission belts are used in general industrial machinery, OA equipment, and the like. The polyurethane transmission belt is a prepolymer comprising a polyisocyanate such as tolylene diisocyanate and a polytetramethylene ether glycol. A material for belt forming of a curing agent such as 1'-methylene bis(o-chloroaniline), a plasticizer, and other additives. This belt forming material is injected into a metal mold for belt forming, thermally cured to have a cylindrical shape, and then circumscribed at a required width to produce a polyurethane transmission belt.

Since the polyurethane transmission belt is used for a long period of time in which tension is applied, there is a demand for improving durability.

Patent Document 1 proposes a polyurethane transmission belt that contains a fat or oil having a melting point of 50 to 80 ° C as a main component of triglyceride as a lubricant to improve durability. The polyurethane drive belt contains Oils and fats with a melting point of 50 to 80 ° C, so the durability is improved when used in the temperature range from room temperature to 50 ° C, but at low temperatures below room temperature, the grease will ooze out of the belt surface and spray (bloom) ), there is a problem of insufficient durability in a low temperature environment.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2012-251586

The present invention provides a polyurethane transmission belt excellent in durability and a material for belt forming for manufacturing the transmission belt.

The configuration of the present invention for solving the above problems is as follows.

(1) A polyurethane transmission belt comprising diisodecyl ester of 1,2-cyclohexanedicarboxylate.

(2) The polyurethane transmission belt according to (1), which contains the aforementioned 1,2-cyclohexanedicarboxyl with respect to 100 parts by weight of the prepolymer synthesized from the polyisocyanate and the polyol. Diisodecyl phthalate is 5 to 40 parts by weight.

(3) The polyurethane transmission belt according to (1) or (2), which has a Shore-A hardness of 85 to 93.

(4) The polyurethane transmission belt according to any one of (1) to (3), which does not contain a phthalate-based plasticizer.

(5) The polyurethane transmission belt according to any one of (1) to (4), which is a Vee belts or a toothed belt.

(6) A material for forming a belt, comprising at least a prepolymer synthesized from a polyisocyanate and a polyhydric alcohol, and diisodecyl 1,2-cyclohexanedicarboxylate.

Diisodecyl 1,2-cyclohexanedicarboxylate, which is a high-performance plasticizer, has excellent bleedout properties, so it bleeds out of the surface of the belt and functions as a lubricant or a surface protective agent. Further, since diisodecyl 1,2-cyclohexanedicarboxylate has excellent non-volatile properties, it remains on the surface of the belt for a long period of time, and its effect as a lubricant or a surface protective agent lasts. Therefore, the durability of the polyurethane transmission belt can be improved by containing diisononyl 1,2-cyclohexanedicarboxylate.

1‧‧‧toothed belt

2‧‧‧ belt teeth

3‧‧‧heart line

Fig. 1 is a view showing the structure of a drive belt.

The polyurethane transmission belt of the present invention contains diisodecyl 1,2-cyclohexanedicarboxylate (i.e., hydrogenated DINP) which is a high-performance plasticizer represented by the following chemical formula (1).

The hydrogenated DINP is obtained by hydrogenating diisodecyl phthalate (DINP) which is a conventional plasticizer and reducing the benzene ring to cyclohexane. The plasticizer blended in the polyurethane transmission belt has a viscosity that reduces the material for forming the belt to improve the formability, and the belt to be softened to improve the flexibility and the cold resistance, and the belt is oozing out. The surface protects the surface to improve the lubricity and durability.

The di-(2-ethylhexyl) phthalate (DOP) represented by the following chemical formula (2) and the dioctyl adipate (DOA) represented by the following chemical formula (3) are used. Plasticizer, hydrogenated DINP is a high-performance plasticizer that greatly enhances the durability of polyurethane drive belts.

The melting point, boiling point, and molecular weight of hydrogenated DINP, DOP, and DOA are listed in Table 1.

The hydrogenated DINP has a melting point of -54 ° C and is liquid at room temperature. Further, it has a cyclohexane ring which is softer than an aromatic ring, and a side chain which is small in branch and linear. Since hydrogenated DINP has a soft molecular structure and a small volume, it is easy to move in a three-dimensional network structure containing polyurethane, and has excellent overflow property. Further, it has a large molecular weight of 424 and a high boiling point of 394 ° C, and is excellent in nonvolatileity.

The DOP system has almost the same melting point as the hydrogenated DINP. However, DOP has a hard benzene ring and a branched 2-ethylhexyl chain, so the molecular structure is hard and bulky. Therefore, compared to hydrogenated DINP, DOP is not easily moved in a three-dimensional network structure containing polyurethane, and its overflow property is poor.

The DOA has a low melting point of -70 °C. The molecular structure of DOA does not have a ring structure, but is soft and linear, so it is easy to move in a three-dimensional mesh structure containing polyurethane, and has superior overflow property than hydrogenated DINP. However, DOA has a low boiling point of 335 ° C, so it is not volatile.

Hydrogenated DINP significantly improves durability over previous plasticizers The effect is due to the fact that hydrogenated DINP has both excellent overflow and non-volatility. The hydrogenated DINP system has excellent spillability and has a function of oozing out of the belt surface to lubricate the belt and the pulley to be lubricated as a lubricant and a surface protective agent. Further, since hydrogenated DINP has excellent non-volatility and is not easily volatilized, it remains on the surface of the belt and the pulley for a long period of time, so that it functions as a lubricant and a surface protective agent. Further, the effect of softening the polyurethane drive belt by the hydrogenated DINP is also long, so that the polyurethane drive belt is not easily hardened by the change over time.

The polyurethane transmission belt of the present invention is produced by thermally curing a belt forming material containing at least a prepolymer and hydrogenated DINP in a mold frame. The curing agent for curing the material for forming a belt is not particularly limited, and examples thereof include 1,1'-methylenebis(o-chloroaniline) (MOCA), dimethylthiotoluenediamine, and diethyltoluene. A polyamine such as an amine, a polyhydric alcohol such as 1,4-butanediol or trimethylolpropane.

In the present invention, the polyisocyanate or the polyol used in the synthesis of the prepolymer is not particularly limited.

As the polyisocyanate, those having two or more isocyanato groups in the molecule can be used without particular limitation. For example, tolylene diisocyanate, tolidine diisocyanate, diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, carbodiimide can be used. Carbodiimidized diphenylmethane polyisocyanate, crude diphenylmethane diisocyanate Ester, xylylene diisocyanate, 1,5-naphthyl diisocyanate, tetramethyxylene diisocyanate, isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenation M-xylylene diisocyanate, hexamethylene diisocyanate, dimer acid diisocyanate, norbornene diisocyanate, and the like. Among these, two or more types can be used together.

In the case of the polyol, those having two or more hydroxyl groups in the molecule can be used without particular limitation. For example, polyether polyols such as polyethylene glycol, polypropylene glycol, and polytetramethylene ether glycol; and adipic acid, sebacic acid, and methylene succinic acid (itaconic acid) ), maleic anhydride, p-nonanoic acid, isophthalic acid, fumaric acid, succinic acid, oxalic acid, malonic acid, glutaric acid, pimelic acid, suberic acid, sebacic acid, etc. a compound with ethylene glycol, diethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, 1,2-propanediol, 1,3-propane a polyester polyol obtained by reacting a polyol compound such as a diol, 1,9-nonanediol, 3-methyl-1,5-pentanediol, tripropylene glycol, trimethylolpropane or glycerin; Polycaprolactone polyol, poly-β-methyl-δ-valerolactone and other polylactone polyester polyols; 1,3-propanediol, 1,4-butanediol, 1, a diol compound such as 6-hexanediol, diethylene glycol, polyethylene glycol, polypropylene glycol or polytetramethylene glycol, and phosgene, dialkyl carbonate or diphenyl carbonate. Polycarbonate polyol obtained by the reaction; polybutadiene polyol, poly Polyolefin polyols and polyol-pentadiene and the like. From these, two or more types can be used together. Further, these may be used in combination with other low molecular weight polyols.

As the low molecular weight polyol to be used together, for example, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 2-methyl-1,3-propanediol, 2- Butyl-2-ethyl-1,3-propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol (ie 2,2-dimethyl-1, 3-propanediol), 2-isopropyl-1,4-butanediol, 3-methyl-2,4-pentanediol, 2,4-pentanediol, 1,5-pentyl Alkanediol, 3-methyl-1,5-pentanediol, 2-methyl-2,4-pentanediol, 2,4-dimethyl-1,5-pentanediol, 2 , 4-diethyl-1,5-pentanediol, 1,5-hexanediol, 1,6-hexanediol, 2-ethyl-1,3-hexanediol, 2- Ethyl-1,6-hexanediol, 1,7-heptanediol, 3,5-heptanediol, 1,8-octanediol, 2-methyl-1,8-octane An aliphatic diol such as a diol, a 1,9-nonanediol or a 1,10-decanediol; a cyclohexanedimethanol (for example, 1,4-cyclohexanedimethanol) or a cyclohexanediol ( For example, 1,3-cyclohexanediol, 1,4-cyclohexanediol), alicyclic diol such as 2-bis(4-hydroxycyclohexyl)-propane; trimethylolethane, trihydroxyl Methylpropane, hexitols, pentitols, glycerin, polyglycerol, pentaerythritol (pen A ternary or higher polyhydric alcohol such as taerythritol), dipentaerythritol or tetramethylolpropane.

The ratio of the prepolymer to the hardener is determined by the number of functional groups of each compound. Specifically, from the viewpoint of obtaining the characteristics of the polyurethane such as strength, it is preferred to use an isocyanate (NCO) group of the prepolymer and an active hydrogen group of the functional group of the hardener. The ear ratio (NCO/active hydrogen group) is adjusted in such a range as 1.2 to 0.9. It is more preferably in the range of 1.1 to 1.02. The type of the active hydrogen group of the curing agent is not particularly limited, and examples thereof include a hydroxyl group, an amine group, an imido group, a carboxyl group, a urethane group, a thiol group, and an epoxy group.

A polyurethane transmission belt is produced by thermally curing a belt forming material containing at least a prepolymer and hydrogenated DINP in a metal mold. Therefore, the prepolymer synthesized from the polyisocyanate and the polyol is preferably liquid in order to be injected into the mold.

The polyurethane transmission belt of the present invention preferably contains 5 to 40 parts by weight of hydrogenated DINP based on 100 parts by weight of the prepolymer. More preferably, it contains 10 to 30 parts by weight, particularly preferably 20 to 30 parts by weight. When the content of the hydrogenated DINP is less than 5 parts by weight, the hydrogenated DINP is insufficiently bleed out on the surface of the belt, so that lubricity and surface protection are not obtained, and the effect of protecting the surface of the belt is weak. When the content of the hydrogenated DINP is more than 40 parts by weight, the polyurethane obtained after curing becomes too soft and has poor durability, and is easily broken when it is formed into a transmission belt.

The polyurethane transmission belt of the present invention may contain a lubricant, a surfactant, a filler, a pigment, a dye, a hydrolysis inhibitor, a reaction accelerator, and the like as needed. The polyurethane transmission belt of the present invention is improved in lubricity by containing hydrogenated DINP, and therefore may not contain a lubricant. Further, when the hydrogenated DINP is contained in the range of 5 to 40 parts by weight, other plasticizers such as DOA may be blended. However, phthalates such as DOP and DINP are strongly suspected to be endocrine disrupting substances, and their reproductive toxicity is worrying, so it is preferable to dispose.

The shape of the polyurethane transmission belt of the present invention is not particularly limited, and can be used as a toothed belt, a V-shaped belt, a flat belt, a round belt or the like.

Polyurethane transmission belt belonging to the present invention A toothed belt of one form is shown in Fig. 1. The toothed belt 1 is formed by a belt body which is provided with a plurality of belt teeth 2 at a predetermined interval on the inner circumferential surface in the belt length direction. Further, along the bottom of each of the belt teeth 2, the core wire 3 as a tensile body is slightly in the belt longitudinal direction, and is provided in a periodic spiral shape in the belt width direction.

The core wire 3 is not particularly limited as long as it has an effective strength as a tensile body, and examples thereof include glass fiber, carbon fiber, guanamine fiber, and polyester fiber.

Next, a method of manufacturing the toothed belt will be described.

<Heartline installation procedure>

The core wires are wound in a spiral shape at predetermined intervals on the outer peripheral surface of the cylindrical inner metal mold. In the inner metal mold, a belt tooth groove is formed on the outer peripheral surface thereof at a predetermined interval and extending in the axial direction. Then, the inner metal mold is inserted into the center of the cylindrical outer metal mold to form a cavity for injecting the material for belt forming between the inner metal mold and the outer metal mold.

<Material preparation steps for belt forming>

A liquid prepolymer synthesized from a polyisocyanate and a polyhydric alcohol, and a hydrogenated DINP and other additives belonging to an optional component are mixed to form a material for belt forming.

<Material injection for belt forming ‧ Hardening step>

The obtained material for belt forming is injected into a cavity between the inner metal mold and the outer metal mold, and is heated to thermally harden the belt forming material.

<Mold release step>

Cylindrical polyurethane made of a material for forming a belt The ester drive belt precursor is released from the metal mold.

<Width cutting step>

The demolded polyurethane belt precursor was cut into a predetermined width by a ring to obtain a polyurethane transmission belt.

Further, the present invention will be described in more detail by way of examples, but the invention is not limited thereto.

<Example 1>

2,4-tolylene diisocyanate was reacted with polytetramethylene ether glycol to synthesize a liquid prepolymer having an NCO group of 5.7 wt%. 100 parts by weight of this prepolymer, 5 parts by weight of hydrogenated DINP (manufactured by BASF Corporation, trade name: Hexamoll DINCH) as a high-performance plasticizer, and 16 parts by weight of MOCA as a curing agent were blended to prepare a material for belt forming. .

This belt forming material was molded, and after curing at 100 ° C for 1 hour, it was cured, and then allowed to stand at 100 ° C for 4 hours to be aged to obtain a sheet 1 having a thickness of 2 mm. Further, according to the method for producing a toothed belt, the belt forming material has a glass fiber cable as a core wire having a circumference of 200 mm, a belt width of 4 mm, and a pitch of 2 mm in the same curing condition as the above-mentioned sheet. The inner peripheral surface has a belt-toothed polyurethane drive belt 1.

<Example 2>

A sheet 2 and a polyurethane transmission belt 2 were produced in the same manner as in Example 1 except that the amount of the hydrogenated DINP was changed to 10 parts by weight.

<Example 3>

A sheet 3 and a polyurethane transmission belt 3 were produced in the same manner as in Example 1 except that the amount of the hydrogenated DINP was changed to 20 parts by weight.

<Example 4>

A sheet 4 and a polyurethane transmission belt 4 were produced in the same manner as in Example 1 except that the amount of the hydrogenated DINP was changed to 30 parts by weight.

<Example 5>

A sheet 5 and a polyurethane transmission belt 5 were produced in the same manner as in Example 1 except that the amount of the hydrogenated DINP was changed to 40 parts by weight.

<Example 6>

The same procedure as in Example 1 was carried out, except that the amount of the hydrogenated DINP was changed to 15 parts by weight, and 15 parts by weight of dioctyl adipate (DOA) which is conventionally used as a plasticizer for polyurethane was prepared. Sheet 6 and polyurethane drive belt 6.

<Comparative Example 1>

A sheet 7 and a polyurethane transmission belt 7 were produced in the same manner as in Example 4 except that the hydrogenated DINP was changed to DOP.

<Comparative Example 2>

A sheet 8 and a polyurethane transmission belt 8 were produced in the same manner as in Example 4 except that the hydrogenated DINP was changed to DOA.

<Comparative Example 3>

In addition to changing the amount of hydrogenated DINP to 3 parts by weight, In the same manner as in Example 1, a sheet 9 and a polyurethane transmission belt 9 were produced.

<Comparative Example 4>

A sheet 10 and a polyurethane transmission belt 10 were produced in the same manner as in Example 1 except that the amount of the hydrogenated DINP was changed to 45 parts by weight.

The blending amounts of the plasticizers of the examples and the comparative examples are shown in the second table.

(test evaluation method)

‧hardness

The hardness of the sheet having a thickness of 2 mm was measured by a Shore A durometer.

‧ glass transition temperature (Tg)

A test piece of 5 mm × 40 mm was cut out from a sheet having a thickness of 2 mm, dynamic viscoelasticity was measured at a frequency of 10 Hz, and Tg was measured from the peak top temperature of the loss coefficient (tan δ).

‧ Spillover

The ring-shaped polyurethane drive belt was cut. The outer peripheral surface on which the belt teeth are not formed is defined as the inner side, and one of the substantially central portions in the longitudinal direction is bent into a ring having a diameter of about 1 cm, and is fixed without applying a compressive stress to the outer peripheral surface on which the belt teeth are not formed. After standing at 23 ° C for 24 hours in a fixed state, the plasticizer oozing out of the outer peripheral surface was wiped with a cloth woven cloth containing no solvent. The difference between the weight before the test and the weight after the plasticizer was wiped was expressed as the relative index of Comparative Example 1 as 100, and the overflow property of the plasticizer was evaluated. The larger the value of the index, the more easily the plasticizer oozes out.

‧ belt life

The polyurethane transmission belt is wound around a drive pulley having a pulley number of 20 and a follower pulley having a pulley number of 20. The belt was operated at room temperature with the number of rotations of the drive pulley set to 2500 rpm, the load of the follower pulley set to 0.29 N‧ m, and the belt initial tension set to 29.4 N.

The belt running time from the start of the running of the belt to the cutting was measured, and the belt running time of Comparative Example 1 was expressed as a relative index of 100, and the belt life was evaluated.

‧heat reduction

The transmission belts 4, 7, and 8 containing 30 parts by weight of the plasticizer were allowed to stand in an oven at 100 ° C for 168 hours. The difference between the initial weight of the transmission belt before the test and the weight of the transmission belt taken out from the oven was expressed by the following equation, and the heating loss was evaluated.

Heating loss = (initial weight - weight after test) / initial weight × 100 (%)

The results of each measurement are shown in Table 3.

〔to sum up〕

The results of the overflow and heating reduction of Example 4 and Comparative Examples 1 and 2, It was confirmed that the hydrogenated DINP has a superior overflow and non-volatile high-performance plasticizer compared to DOP and DOA.

Compared with Comparative Examples 1 and 2 containing DOP and DOA, 5 to 40 parts by weight of the hydrogenated DINP containing a high-functional plasticizer can further achieve a long-term life of the belt.

The overflow of Comparative Example 3 containing 3 parts by weight of hydrogenated DINP was greatly reduced as compared with Example 1 containing 5 parts by weight of hydrogenated DINP. Therefore, the amount of bleeding of the hydrogenated DINP on the surface of the belt was small, and the lubricity and surface protection were inferior, and the belt life was the same as in Comparative Example 1.

The belt of Comparative Example 4 containing 45 parts by weight of hydrogenated DINP had a belt life of only about half of that of the transmission belt of Example 5 containing 40 parts by weight of hydrogenated DINP. This is due to the excessive amount of hydrogenated DINP, which makes the rubber too soft. The belt life was shorter than Comparative Example 1.

1‧‧‧toothed belt

2‧‧‧ belt teeth

3‧‧‧heart line

Claims (6)

A polyurethane transmission belt comprising diisodecyl 1,2-cyclohexanedicarboxylate represented by the following chemical formula (1) The polyurethane transmission belt according to claim 1, wherein the 1,2-cyclohexanedicarboxylate is contained in an amount of 100 parts by weight based on 100 parts by weight of the prepolymer synthesized from the polyisocyanate and the polyol. Diisodecyl phthalate is 5 to 40 parts by weight. The transmission belt made of polyurethane according to the first or second aspect of the patent application has a Shore A hardness of 85 to 93. The polyurethane transmission belt according to any one of claims 1 to 3 is a phthalate-free plasticizer. The polyurethane transmission belt according to any one of claims 1 to 4, which is a V-shaped belt or a toothed belt. A material for belt forming contains at least a prepolymer synthesized from a polyisocyanate and a polyhydric alcohol, and diisodecyl 1,2-cyclohexanedicarboxylate.